50 BULLETIN 1406, U. S. DEPARTMENT OF AGRICULTURE 



There was no consistent variation in the quantity either of total 

 or reducing sugar depending upon the temperature at which the 

 fruit was held while ripening. 



Acidity decreased between the time of picking and that of full 

 ripeness in all varieties and at all temperatures. On the average, 

 the decrease was greatest in fruit held at the highest temperatures. 

 At 40° to 60° F. there was only a slight decrease in acidity. At 

 32° and 30° the decrease was variable, in some varieties being large 

 and in others slight. 



On the whole, there was a close agreement between the respiration 

 and the softening rates in apples. The respiration rate at 40° F. 

 was almost double that at 32°, while the rate at 60° was about three 

 times that at 40°. The softening rates in most cases were in about 

 the same order. 



The respiratory ratio was practically always slightly more than 1, 

 the ratio for the complete oxidation of dextrose, and less than 1.33, 

 the ratio for the complete oxidation of malic acid, indicating that at 

 all temperatures both acid and sugars were being oxidized. At 85° 

 and 32° F. the ratio averaged slightly higher than at 40° and 60°, 

 indicating that a somewhat larger proportion of acid was being 

 oxidized at these extreme temperatures than at intermediate tem- 

 peratures. 



